Scavenging oxygen

Abstract

A container (22) includes an oxygen-sensitive beverage, for example a vitamin C-containing beverage. A closure (40) seals the mouth (28) of container (22). The closure includes an oxygen scavenging structure, for example a closure, which comprises a hydrogen generating means and a catalyst for catalysing a reaction between hydrogen and oxygen.

Claims

1. A container comprising an oxygen scavenging structure (herein referred to as the OSS), wherein the OSS is secured relative to a permeable container body of the container, wherein said container body includes no catalyst added for catalyzing a reaction between hydrogen and oxygen; wherein the OSS comprises a hydrogen generating means which includes active material arranged to generate molecular hydrogen on reaction with moisture, wherein said hydrogen generating means is arranged to generate molecular hydrogen for at least 90 days, and a catalyst for catalysing a reaction between hydrogen and oxygen; wherein said OSS includes a control means for controlling the passage of moisture to said active material; wherein at least part of said control means is provided in a first layer and a second layer comprises said hydrogen generating means, which comprises a matrix with which said active material is associated; wherein catalyst is dispersed in said first layer or said second layer, wherein the sum of the volume of the first and second layers is defined as the sum-vol in mm.sup.3, and said OSS includes less than 0.20 g of catalyst per unit of said sum-vol in mm.sup.3; and wherein said first layer includes at least 70 wt % of the total amount of catalyst in the OSS; wherein said control means is arranged to control a first evolution ratio, wherein the first evolution ratio is defined as: $\frac{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\mathrm{container}\\ \mathrm{over}a\mathrm{selected}\mathrm{initial}5\mathrm{day}\mathrm{period}\end{array}}{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\\ \mathrm{container}\mathrm{over}a\mathrm{second}5\mathrm{day}\mathrm{period}\mathrm{starting}\\ 85\mathrm{days}\mathrm{after}\mathrm{the}\mathrm{end}\mathrm{of}\mathrm{the}\mathrm{selected}\mathrm{initial}\mathrm{period}\end{array}}$ and wherein said first evolution ratio is less than 4 and is greater than 0.5.

2. A container according to claim 1, wherein said OSS includes a first structure area which is defined by a face of the OSS which has the greatest area, wherein said OSS includes less than 0.01 g of catalyst per unit area in mm.sup.2 of said first structure area.

3. A container according to claim 1, wherein said catalyst is dispersed within one or more materials, wherein the material or materials within which the catalyst is dispersed occupy a first structure volume within the OSS, wherein the first structure volume is of less than 15000 mm.sup.3 and is at least 100 mm.sup.3.

4. A container according to claim 3, wherein said first structure volume includes 0.00000050 g to 0.000160 g of catalyst.

5. A container according to claim 1, wherein a catalyst volume-area ratio (CVR) is defined as follows: $\mathrm{CVR}\left(\mathrm{in}\mathrm{mm}\right)=\frac{\begin{array}{c}\mathrm{total}\mathrm{volume}\mathrm{of}\mathrm{material}\left(s\right)\\ \mathrm{in}\mathrm{which}\mathrm{catalyst}\mathrm{is}\mathrm{dispersed}\end{array}}{\begin{array}{c}\mathrm{the}\mathrm{area}\mathrm{of}a\mathrm{face}\mathrm{of}\mathrm{said}\mathrm{volume}\\ \mathrm{which}\mathrm{has}\mathrm{the}\mathrm{greatest}\mathrm{area}\end{array}}$ wherein said CVR is at least 0.2.

6. A container according to claim 1 wherein said first and second layers together include less than 50 ppm of catalyst.

7. A container according to claim 1, wherein the maximum thickness of said first layer is less than 5 mm and the maximum thickness of said second layer is less than 3 mm.

8. A container according to claim 1, wherein said OSS includes a catalyst-containing structure which includes three or fewer layers and said catalyst-containing structure has a surface area which is exposed to the inside of a container body in use, wherein said surface area is less than 5000 mm.sup.2.

9. A container according to claim 1, wherein the ratio of the weight of hydrogen generating means divided by the weight of catalyst in said OSS is in the range 50-20000.

10. A container according to claim 1, wherein said closure includes less than 0.000200 g and at least 0.00000050 g of catalyst and/or wherein said closure includes less than 10 ppm and at least 1 ppm of catalyst based on the total weight of said closure.

11. A container according to claim 10, wherein said catalyst is dispersed within one or more materials which are associated with said closure, wherein said one or more materials occupy a first volume within the closure, wherein said first volume is less than 15000 mm.sup.3 and is at least 100 mm.sup.3.

12. A container according to claim 10, wherein the maximum thickness of said first layer of said closure is less than 5 mm, said first and second layers of said closure together include less than 50 ppm of catalyst and said second layer has a maximum thickness of less than 3 mm.

13. A container according to claim 10, wherein the hydrogen generating means is provided in said second layer and the ratio of the weight of hydrogen generating means divided by the weight of polymeric matrix is in the range 0.02 to 0.25; and/or the ratio of the weight of hydrogen generating means divided by the weight of catalyst in said closure is in the range 50-20000.

14. A container according to claim 1, wherein said container includes a product having an oxygen specification of 20 w/v ppm.

15. A container according to claim 1, wherein said container body has an internal volume for containing products and said OSS includes less than 0.001 g of catalyst per unit internal volume in mm.sup.3 of the container body.

16. A container according to claim 1, wherein said first layer is closer to the contents of the container body in use than said second layer.

17. A container according to claim 1, wherein said OSS is in the form of a closure which is secured relative to said container body, wherein said closure includes a screw-threaded area for releasably securing the closure to the container body.

18. A container according to claim 17, wherein said OSS includes a catalyst containing structure which includes said first layer and said second layer, wherein said catalyst-containing structure has a surface area which is exposed to the inside of the container body, wherein said surface area is less than 5000 mm.sup.3.

19. A container according to claim 1, wherein said container body has an internal volume for containing products and said OSS includes less than 0.001 g of catalyst per unit internal volume in mm.sup.3 of the container body; wherein said first layer is closer to the contents of the container body in use than said second layer; wherein said OSS is in the form of a closure which is secured relative to said container body, wherein said closure includes a screw-threaded area for releasably securing the closure to the container body; and wherein said OSS includes a catalyst containing structure which includes said first layer and said second layer, wherein said catalyst-containing structure has a surface area which is exposed to the inside of the container body, wherein said surface area is less than 5000 mm.sup.3.

20. A method of protecting an oxygen sensitive consumable against deterioration as a result of contact with oxygen, the method comprising packing the consumable in a container which includes a closure incorporating an oxygen scavenging structure (herein referred to as the OSS), wherein the OSS is secured relative to a permeable container body of the container, wherein said permeable container body includes no catalyst added for catalyzing a reaction between hydrogen and oxygen; wherein the OSS comprises a hydrogen generating means which includes active material arranged to generate molecular hydrogen on reaction with moisture and catalyst for catalyzing a reaction between hydrogen and oxygen; wherein said OSS includes a control means for controlling the passage of moisture to said active material; wherein at least part of said control means is provided in a first layer and a second layer comprises said hydrogen generating means, which comprises a matrix with which said active material is associated; wherein catalyst is dispersed in said first layer or said second layer, wherein the sum of the volume of the first and second layers is defined as the sum-vol in mm.sup.3, and said OSS includes less than 0.20 g of catalyst per unit of said sum-vol in mm.sup.3, wherein said first layer includes at least 70 wt % of the total amount of catalyst in the OSS; wherein said hydrogen generating means is arranged to generate molecular hydrogen for at least 90 days; wherein said control means is arranged to control a first evolution ratio, wherein the first evolution ratio is defined as: $\frac{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\mathrm{container}\\ \mathrm{over}a\mathrm{selected}\mathrm{initial}5\mathrm{day}\mathrm{period}\end{array}}{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\\ \mathrm{container}\mathrm{over}a\mathrm{second}5\mathrm{day}\mathrm{period}\mathrm{starting}\\ 85\mathrm{days}\mathrm{after}\mathrm{the}\mathrm{end}\mathrm{of}\mathrm{the}\mathrm{selected}\mathrm{initial}\mathrm{period}\end{array}}$ and wherein said first evolution ratio is less than 4 and is greater than 0.5.

21. A container comprising an oxygen scavenging structure (herein referred to as the OSS), wherein the OSS is secured relative to a permeable container body of the container, wherein said container body includes no catalyst added for catalyzing a reaction between hydrogen and oxygen; wherein the OSS comprises a hydrogen generating means which includes active material arranged to generate molecular hydrogen on reaction with moisture, wherein said hydrogen generating means is arranged to generate molecular hydrogen for at least 90 days, and a catalyst for catalysing a reaction between hydrogen and oxygen; wherein said OSS includes a control means for controlling the passage of moisture to said active material; wherein at least part of said control means is provided in a first layer and a second layer comprises said hydrogen generating means, which comprises a matrix with which said active material is associated; wherein catalyst is dispersed in said first layer or said second layer, wherein the sum of the volume of the first and second layers is defined as the sum-vol in mm.sup.3 and said OSS includes less than 0.20 g of catalyst per unit of said sum-vol in mm.sup.3; wherein said first layer includes at least 70 wt % of the total amount of catalyst in the OSS; wherein said container body has an internal volume for containing products and said OSS includes less than 0.001 g of catalyst per unit internal volume in mm.sup.3 of the container body; wherein said first layer is closer to the contents of the container body in use than said second layer; wherein said OSS is in the form of a closure which is secured relative to said container body, wherein said closure includes a screw-threaded area for releasably securing the closure to the container body; wherein said OSS includes a catalyst containing structure which includes said first layer and said second layer, wherein said catalyst-containing structure has a surface area which is exposed to the inside of the container body, wherein said surface area is less than 5000 mm.sup.3; wherein a catalyst volume-area ratio (CVR) is defined as follows: $\mathrm{CVR}\left(\mathrm{in}\mathrm{mm}\right)=\frac{\begin{array}{c}\mathrm{total}\mathrm{volume}\mathrm{of}\mathrm{material}\left(s\right)\\ \mathrm{in}\mathrm{which}\mathrm{catalyst}\mathrm{is}\mathrm{dispersed}\end{array}}{\begin{array}{c}\mathrm{the}\mathrm{area}\mathrm{of}a\mathrm{face}\mathrm{of}\mathrm{said}\mathrm{volume}\\ \mathrm{which}\mathrm{has}\mathrm{the}\mathrm{greatest}\mathrm{area}\end{array}}$ wherein said CVR is at least 0.2; wherein said control means is arranged to control a first evolution ratio, wherein the first evolution ratio is defined as: $\frac{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\mathrm{container}\\ \mathrm{over}a\mathrm{selected}\mathrm{initial}5\mathrm{day}\mathrm{period}\end{array}}{\begin{array}{c}\mathrm{the}\mathrm{rate}\mathrm{of}\mathrm{evolution}\mathrm{of}\mathrm{hydrogen}\mathrm{in}\mathrm{the}\\ \mathrm{container}\mathrm{over}a\mathrm{second}5\mathrm{day}\mathrm{period}\mathrm{starting}\\ 85\mathrm{days}\mathrm{after}\mathrm{the}\mathrm{end}\mathrm{of}\mathrm{the}\mathrm{selected}\mathrm{initial}\mathrm{period}\end{array}}$ and wherein said first evolution ratio is less than 4 and is greater than 0.5.

Description

(1) Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying figures, in which:

(2) FIG. 1 is a schematic representation of a juice bottle incorporating oxygen scavenging technology;

(3) FIG. 2 is a cross-section through a preform;

(4) FIG. 3 is a cross-section through a bottle;

(5) FIG. 4 is a side elevation of a bottle including a closure;

(6) FIG. 5 is a closure, partly in cross-section;

(7) FIG. 6 is a plot of vitamin C in ppm v. time in days for a range of different containers/liners;

(8) FIG. 7 is an alternative closure, partly in cross-section; and

(9) FIG. 8 is a further alternative closure, partly in cross-section.

(10) The following materials are referred to hereinafter:

(11) HyCat-1 (product code 280-10120-1)a 0.42 wt % dispersion of palladium acetate in an inert carrier. available from Colormatrix;

(12) HyCat Base-1 (product code 280-10119-1)a 1 wt % dispersion of palladium acetate in an inert carrier available from Colormatrix;

(13) Ti818refers to a grade of PET resin, obtained from Wellman Inc. It is a PET-resin which does not contain any antimony;

(14) EVAethylvinylacetate copolymer (Elvax 760 from DuPont) with vinyl acetate content of 9.3% and a melt flow index (190 C./2.16 kg)) of 2.0 g/10 min (ASTM D1238) was used as received;

(15) EVAethylvinylacetate copolymer (Elvax 550 from DuPont) with vinyl acetate content of 15% and a melt flow index (190 C./2.16 kg)) of 8.0 g/10 min (ASTM D1238) was used as received;

(16) HDPEHigh density polyethylene (Rigidex HD5211EA from) Ineos was used as received;

(17) Sodium Borohydride (Venpure SF) from Dow was used as received;

(18) Flowrefers to a grade of PET resin, obtained from La Seda de Barcelona.

(19) In the figures, the same or similar parts are annotated with the same reference numerals.

(20) A preform 10 illustrated in FIG. 2 can be blow molded to form a container 22 illustrated in FIG. 3. The container 22 comprises a shell 24 comprising a threaded neck finish 26 defining a mouth 28, a capping flange 30 below the threaded neck finish, a tapered section 32 extending from the capping flange, a body section 34 extending below the tapered section, and a base 36 at the bottom of the container. The container 22 is suitably used to make a packaged beverage 38, as illustrated in FIG. 4. The packaged beverage 38 includes a beverage. In one particular embodiment, the beverage is an oxygen sensitive beverage. It may be a vitamin C containing beverage such as a vitamin C containing fruit juice, a beverage which has been fortified with vitamin C, or a combination of juices in which at least one of the juices includes vitamin C. The beverage is disposed in the container 22 and a closure 40 seals the mouth 28 of container 22.

(21) Referring to FIG. 5, a circular cross-section aseptic closure 40 is shown which includes a closure shell 42 with a screw-threaded portion 44 for screw-threadedly engaging the closure with a threaded neck finish 26. Within the diameter of a sealing well 46 is a disc-shaped insert 48 which is moulded to inwardly facing wall 49 of shell 42. The insert 48 may include an inner layer 50 and an outer layer 52. The outer layer is suitably overmoulded around layer 50 suitably so that layer 50 is fully encapsulated. Layer 50 may have a thickness of 1 mm; and layer 52 may have a thickness of 0.3 mm.

(22) Various different containers 22 and closures were made and tested as described below with reference to FIG. 5.

(23) TABLE-US-00001 Example No. Container/Closure construction 1 Container: standard (no palladium catalyst) (comparative) Standard closure including no hydrogen generation means or catalyst 2 Container: Ti818 resin containing 2 ppm palladium (comparative) Closure: Layer 50 - includes sodium borohydride - 8 Wt. % in EVA (Elvax 760) Layer 52: EVA (Elvax 550) 3 Container: Flow resin (no palladium catalyst) Closure: Layer 50 - includes sodium borohydride 8 Wt. % in EVA (Elvax 760) plus 40 ppm palladium Layer 52 - EVA (Elvax 550) 4 Container: Flow resin Closure: Layer 50 - includes sodium borohydride - 8 Wt. % in EVA (Elvax 760) Layer 52 - EVA (Elvax 550) containing 40 ppm palladium 5 Container: Flow resin Closure: Layer 50 - includes sodium borohydride - 8 Wt. % in EVA (Elvax 760) plus 20 ppm palladium Layer 52 - EVA (Elvax 550) containing 20 ppm palladium

(24) A summary of loadings and calculated weights of palladium in the closures of the examples is provided in the table below.

(25) TABLE-US-00002 Weight of Pd loading in Pd loading in Example No. Part part (g) part (ppm) part (g) 2 Container 21 2 0.000042 Closure layer 50 0.45 0 0 Closure layer 52 0.37 0 0 3 Container 21 0 0 Closure layer 50 0.45 40 0.000018 Closure layer 52 0.37 0 0 4 Container 21 0 0 Closure layer 50 0.45 0 0 Closure layer 52 0.37 40 0.0000148 5 Container 21 0 0 Closure layer 50 0.45 20 0.000009 Closure layer 52 0.37 20 0.0000074

EXAMPLE 6

Preparation of Container Incorporating Palladium

(26) HyCat-1 was blended with PET at 0.1 wt. % to provide 2 ppm palladium in the resin. The blend was injection moulded into 21 g preforms and 330 ml bottles were blown from the preforms.

EXAMPLE 7

Preparation of Sodium Borohydride/EVA Compound

(27) 2.4 kg of Sodium borohydride (8 wt %) was compounded with 27.6 kg of Elvax 760 (92 wt %) on a 24 mm Thermo Fisher twin screw extruder equipped with a die face cutter. The feed zone temperature was set at 70 C. and the other zones of the extruder were set at 135 C. tapering down to 125 C. at the die. The compound was stored in a dry nitrogen atmosphere in a sealed foil bag.

EXAMPLE 8

Moulding of Sodium Borohydride/EVA Compounds (with and without Pd) into Discs (e.g. Layer 50 of FIG. 5)

(28) The 8 wt % sodium borohydride/EVA compound of example 7 was moulded into discs (26 mm diameter and 1 mm thick) using a Boy 22M injection moulding machine. The feed zone temperature was set at 160 C. and the other zones were set at 200 C. Both the hopper and collection vessel were continuously purged with a dry nitrogen atmosphere. The moulded discs were stored in a dry nitrogen atmosphere in a sealed foil bag.

(29) To incorporate palladium into the 8 wt % sodium borohydride/EVA moulded discs HyCat Base-1 was blended with the 8 wt % sodium borohydride/EVA compound of example 7 by tumble mixing the liquid onto the pellets prior to moulding. The quantity added was modified depending on the amount of Pd required in the final part: for 20 ppm in the final part 0.422 wt % was added, and for 40 ppm in the final part 0.844 wt % was added.

EXAMPLE 9

Moulding of Closures

(30) The sodium borohydride/EVA injection moulded discs 50 of example 8 (with and without Pd) were incorporated into a closure using a Netstal Synergy 1750-600/230 injection moulding machine fitted with two injection moulding units and a linear indexing mould. One injection moulding unit injected an HDPE closure shell (42 in FIG. 5) and one injection moulding unit injected the EVA layer (52 in FIG. 5) to fully encompass the disc 50 containing the sodium borohydride. All injection zones were set at 200 C.

(31) To incorporate palladium into the EVA layer (52 in FIG. 5) HyCat Base-1 was blended with the EVA by tumble mixing the liquid onto the pellets prior to moulding to fully encompass disc 50. The quantity added was modified depending on the amount of Pd required in the final part: for 20 ppm in the final part 0.422 wt % was added, and for 40 ppm in the final part 0.844 wt. % was added.

(32) The moulded closures were stored in a dry nitrogen atmosphere in a sealed foil bag.

EXAMPLE 10

General Procedure for Testing Constructions of Examples 1 to 5

(33) To each PET bottle was added a 330 ml solution of ascorbic acid (500 ppm) and biocide (Baquacil, 1,000 ppm) made up using de-ionized water. No degassing of the liquid or headspace (25 ml) in the bottle was undertaken which means the bottles are especially challenging to de-oxygenate. (Often during commercial bottling both consumables being bottled and the bottle itself are de-gassed during filling). Closures as described in examples 1 to 5 were attached to the bottles and the bottles stored at 20 C. Each of examples 1 to 5 was assessed in triplicate. At each test point, three individual bottles for each test series were tested for ascorbic acid content using a Mettler Toledo G20 Compact Titrator. Results are presented graphically in FIG. 6.

(34) The results show that all examples (example 2 to 5) which include oxygen scavenging arrangements preserve more vitamin C over time relative to the example 1 arrangement for which there is no oxygen scavenging. Examples 3 to 5 have a similar level of performance compared to example 2. This is surprising given the fact vitamin C is very oxygen sensitive implying that rapid oxygen scavenging would be needed to protect it from oxidation, but in examples 3 to 5 the oxygen must travel a substantial distance through the beverage before it comes into contact with the palladium catalyst wherein the oxygen scavenging reaction takes place. In addition, example 2 includes more palladium catalyst (in gsee Table above) distributed throughout the bottle wall over a far greater area than in the closure of examples 3 to 5 and it would be expected that example 2 would be far superior in oxygen scavenging compared to examples 3 to 5. Thus, the cost of catalyst and other manufacturing costs can be reduced by adopting arrangements as in examples 3 to 5, whilst achieving excellent oxygen scavenging ability.

(35) FIG. 7 shows an alternative closure 60 which differs from the closure 40 of FIG. 5 primarily in the design of insert 60. Insert 60 includes an inner layer 62 (which may be made from material(s) as described above for layer 50). Layer 62 is disc-shaped and is fully encapsulated by a layer 64 (which may be made from material(s) as described above for layer 50). Thus, layer 64 defines a core which is fully enclosed within a shell defined by layer 64.

(36) The insert 60 is adhered to wall 49. In general terms, the insert 60 could be heat sealed, welded or glued to wall 49. Thus, the closure 60 may be made in two separate parts (i.e. insert 60 on the one hand and the shell etc on the other hand) and the parts secured together to define the closure 60 for oxygen scavenging.

(37) In an alternative embodiment, an insert similar to insert 60 of FIG. 7 but not associated with a closure may be attached to an internal wall of a container body, for example a lower wall or a side wall. Such an insert may be thermoformed with the container body (e.g. a cup or tray). Alternatively, it may be added after the container body and/or container has been formed and in some cases could be free flowing within the container body (e.g. when an opening used to dispense products from the container is too small for the insert to pass through). Such a free floating or fixed insert, which may be in the form of a disc, patch or sachet, may be associated with various types of containers, such as cups, trays or bottles.

(38) In a further alternative embodiment shown in FIG. 8, material of the closure shell 72a itself acts as a barrier material to control passage of moisture to hydrogen generator 76d which includes active material for generating hydrogen. Closure shell 72a additionally includes 50 ppm of palladium catalyst for catalysing the oxygen scavenging reaction. Alternatively, (or additionally), catalyst may be associated with the hydrogen generator 76d, for example by being mixed therewith.

(39) The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.